The cellular phone has become a prerequisite information product among people living in the modern society, and almost everyone owns a cellular phone now. Among others, the recently developed slide cellular phone has become one of the most widely welcome types of cellular phones among general consumers. The slide cellular phone is internally provided with a sliding mechanism to enable an upper case of the cellular phone to slide relative to a lower case. However, the currently available slide cellular phones still have many disadvantages that require improvement. FIG. 9 is a plan view of a conventional sliding mechanism for a slide cellular phone. As shown, the sliding mechanism includes a lower plate 60, an upper plate 62 slidably connected to a top of the lower plate 60, and an extension arm 63. On the lower plate 60, there is provided an upward projected boss 68, a turn section 70, and a slot 71 having a roller 69 located therein. The extension arm 63 includes a stationary seat 64 connected to the boss 68 on the lower plate 60, a movable seat 65 fitted around the roller 69, two bars 66 each having a first end extended into the stationary seat 64 and a second end fixedly connected to the movable seat 65, and two springs 67 mounted around the two bars 66 to locate between the stationary seat 64 and the movable seat 65.
By pushing the upper plate 62, the upper plate 62 may slide to displace on the lower plate 60. When the roller 69 approaches the turn section 70, a bottom of the roller 69 is caused to move along the edges of the turn section 70 while a top of the roller 69 moves inward along the turn section 70. At this point, the springs 67 are compressed to store elastic energy. When the roller 69 passes through the apex of the turn section 70 and slides to an inclined surface of the turn section 70, the roller 69 starts sliding downward and brings the upper case of the slide cellular phone to an open position as shown in FIG. 9.
The above-described conventional sliding mechanism for cellular phone including a lower plate 60, an upper plate 62, and an extension arm 63 would have a relatively large thickness, which together with other components would largely increase the overall thickness of the cellular phone, making the cellular phone no longer a compact information product satisfying the main features of being small, slim, and light. Moreover, the extension arm 63 is the only member for actuating the conventional sliding mechanism, the upper plate 62 might slide in an unbalanced and unsmooth manner. And, the springs 67 are subject to elastic fatigue, deformation, or elastic failure when the sliding mechanism operates in the unbalanced condition over a long time.